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Bitcoin Anonymity Mike Fleder Mike Kester Sudeep Pillai
"Voodah"1G6EQwiAfTVyTpK4j3XZ65CvonjDGrPsQ
"darkskypoet"1QEZohXPbh4ywbzPJATjMBDnSjJsZrZtQ1
Goal & Results● Attacker Goal
○ Tie “real” name to transactions
● Results○ Linked forum user to Silk Road through 1
intermediaries■ bl4kjaguar ⇒ Friend ⇒ Silk Road ⇒ FBI
1Agy5BVCxFHi34nJxPdAoGh4
XLAwbdP
1QGLRTU2KZ2bx9kJyNFGkZHyxt3VohCPCL
1LkYiL3RaouKXTUhGcE84XLc31JjnLc3
14hstJKLgss5UHMJqrVz8jP6zvxN6mkuWM
What is Bitcoin?
What is Bitcoin?Forums“voodah”
14hstJKLgss5UHMJqrVz8jP6zvxN6mkuWM
Twitter“crash_override”
1Agy5BVCxFHi34nJxPdAoGh4XLAwbdP
1Agy5BVCxFHi34nJxPdAoGh4
XLAwbdP
1QGLRTU2KZ2bx9kJyNFGkZHyxt3VohCPCL
1LkYiL3RaouKXTUhGcE84XLc31JjnLc3
14hstJKLgss5UHMJqrVz8jP6zvxN6mkuWM
Security Description
● Transactions○ Public Ledger○ Complete history of a coin through ledger
● Software○ Most clients imperfect
● Attacker Goal: Tie “real” name to transactions
● Leak 1: (“real” name, public key) revealed together○ Intentional: Forums, donations, social networks○ Unintentional: Inadvertent leaks
● Leak 2: (“real” name, some tx info) revealed together
“Alice, it’s Bob. I sent you ~$100 at ~noon yesterday”
Threat Model
Scraped fromhttps://bitcointalk.org/index.php?all=&topic=143194.0
{'address':set(['1BSmWFDn1bmmfrBZyW1hJHTwZ8apg9w99Y']), 'membername': [‘cyclops']}
Bitcoin key ⇒ “real” names
● Leak 1: Definitivelyvia Forums
● Leak 2: Statisticallyvia Eavesdropping
Graph Analysis User Activity Revealed
De-anonymization Pipeline
“I sent you $100 ± $1, yesterday at noon ± 5 minutes”D
iffic
ulty
Graph Analysis Pipeline
Block Chain Parser “Entity” Graph
Web Scraping(Forums, Social media)
“Casimir1904”1BSmWFDn1bmmfrBZyW1hJHTwZ
8apg9w99Y
User ActivityRevealedTx Graph
Bitcoin “Entity” Graph
PageRank NodesTop 30 nodes 1st order edges
Bitcoin “Entity” Graph
CommunitiesUntraceableTransactions
Single Entity
Large Volume TransactionsEdge thickness indicates value
PageRank NodesTop 30 nodes 1st order edges
Typical Transaction Graph for a day
Annotated “Entity” GraphSilk Road ArrestFBI seized coins sent to a single known public key - Oct 25 2013
Revealed User Bitcointalk.org Forum user
PageRank NodesTop 30 nodes 1st order edges
Annotated Nodes40 scraped annotations
Annotated “Entity” GraphSilk Road ArrestFBI seized coins sent to a single known public key - Oct 25 2013
Revealed User Bitcointalk.org Forum user
PageRank NodesTop 30 nodes 1st order edges
Annotated Nodes40 scraped annotationsThanks!